This invention relates to detergent formulations and more particularly relates to detergent formulations containing alkyl benzene sulfonates.
The alkali metal and ammonium salts of alkyl benzene sulfonates have been used for decades as the active surfactant in synthetic detergent formulations, particularly in the heavy duty laundry detergents used by the American housewife. Such heavy duty laundry detergents typically contain 5 percent or more of an alkyl benzene sulfonate wherein the alkyl chain has between 10 and 15 carbon atoms, which is known to those skilled in the art to be an outstanding surfactant for this purpose.
In particular, such detergent formulations are usually free-flowing substantially dry powders which are prepared by removing water from a blend of the alkyl benzene sulfonate with a filler, a builder, optical brighteners, perfumes and the like. On the other hand, some detergent formulations are prepared by making a physical mixture of the dried alkyl benzene sulfonate on a filler with builders, perfumes, optical brighteners and other detergent ingredients.
Although such products have satisfactory cleaning performance on clothing and hard surfaces, such detergent formulations are frequently hygroscopic, causing the dried detergent to become tacky, and the formulation loses some, if not all, of its free-flowing characteristics. This is particularly true in those detergent formulations where phosphate salts have been removed from the formulation in favor of non-phosphate builders because of the recent emphasis on removing phosphates frpom detergent and cleaning compositions for environmental reasons.
To overcome these problems, those skilled in the art of detergent formulation have added materials to the detergent formulation to reduce the tendency of the dry detergent to cake and to lose its free-flowing characteristics. Although these materials have reduced the tendency of the dry detergent to lose its free-flowing characteristics, the detergent powder frequently becomes tacky and loses its free-flowing characteristics, even with these additives present, because the alkyl benzene sulfonate used in the formulation is so hygroscopic, particularly under high humidity conditions.
Thus, it can be seen that there is a need for a detergent formulation that contains alkyl benzene sulfonate which is an outstanding surfactant for home laundry applications, which is not hygroscopic and thus cause the dry detergent formulation to lose its free-flowing characteristics, with or without special additives to prevent such tackiness.